Socket and contact



Dec. 7, 1954 M. L. MCLEAN ET AL 2,696,535

SOCKET AND CONTACT Filed Sept. 16, 1950 E? 30 lNvr-:NToRS 11' 4 lf ggMARKL. McLEAN lg' 32, Hfnmrnovfnmfn United States Patent C SGCKET ANDCONTACT Ivlark L. McLean and Herbert F. Overmier, Emporium,

Pa., assignors to Sylvania Electric Products Inc., a corporation ofMassachusetts Application September 16, 1950, Serial No. 185,310

3 Claims. (Cl. 20G-51.04)

The present invention relates to plug in sockets and more particularlyto a socket device for testing subminiature tubes which are providedwith long, somewhat flexible wire terminal leads rather than heretoforeconventional contact prongs.

An object of the present invention is the provision of an improvedsocket for subminiature tubes.

Another object of the present invention is the provision of an improvedsocket for making connections to terminals of an electrical device,particularly when making capacity measurements between the internalelements associated with the terminals of the device.

Still another object of the present invention is the provision of asocket device into which flexible terminal leads may be plugged.

Still a further object of the present invention is the provision of asocket device having means for relieving the contact spring pressure tofacilitate the insertion of. terminals of a device to be tested into thesocket.

The foregoing objects and others which may appear from the followingdetailed description are attained in accordance with an aspect of thepresent invention by providing a test socket having a number of terminalor lead receiving apertures properly spaced to receive the long,liexible wires serving as lead-in wires for a subminiature tube.

Each aperture is preferably lined with a conductive sleeve having a sideaperture therein, through which a spring pressed pressure member mayprotrude to securely grip the terminal or lead-in wire between it andthe opposing side wall of the tube, Camming means are provided for eachof the spring plungers, so the spring pressure of the plungers may beselectively applied or released. In the position of the camming meanswhich relaxes the spring pressure, the through apertures in theconductive sleeves by means of which contact is made to the lead-inwires of the tube are substantially free and clear, so that the wiresmay be inserted to their full length with no tendency to bend or buckle.After the tube is inserted, an operation of the cam operating meansapplies the spring pressure to all of the plungers simultaneously, thuspositively making electrical connection between the contact tubes andthe lead-in wires.

Since the present socket arrangement is primarily designed for capacitymeasurement purposes, each contact sleeve is as completely as possibleelectrically shielded from the exterior and from every other contactsleeve by conductive walls, and coaxial cable connectors are provided inconnection with each of the spring pressed plungers whereby a capacitymeasuring bridge or the like may be connected across any pair ofinternal elements of the tube.

The present invention will be more fully understood by reference to thefollowing detailed description which is accompanied by a drawing inwhich Figure 1 illustrates in partial plan view and partially in sectionan embodiment of the present invention with the top shield plateremoved, while Figure 2 is a fragmentary showing of a part of Figure 1in a different operating position.

ldigure 3 is an enlarged view of a detail of Figure l, an

Figure 4 is a sectional view taken along line 4-4 of Figure l but withthe top shield in position.

The partial plan view shown in Figure 1 shows an outer metal ring havinga number of coaxial cable connectors 12 equally spaced about the ringand extending ra- Patented Dec. 7, 1954 ICC dially through the ring. Theconnectors are of conventional construction, having an outer threadedsleeve and a coaxially arranged inner conductor each of which carries anend contact 50. The number of coaxial cable connectors is equivalent tothe maximum number of lead-in conductors 14 of any tube which is to betested. One such tube is shown at 15 in Figure 4. Within ring 10 thereis carried an inner assembly, including a number of pie-shaped sectionsof insulating material 16, each separated from the other by conductiveiins 18. The tins 18 corne together at a common point at the center ofthe inner assembly, and are conductively joined, while at the outer endsthe tins are supported by posts 20. Regularly spaced around thecircumference of a circle, centered at the junction of the fins 18, area number of tubular contact members or sleeves 22, one between each pairof tins 18. Posts 20 which terminate the outer ends of tins 18 arerigidly secured to or are an integral part of bottom plate 23 (Fig. 4),which is received in a rabbet around the lower inner edge of ring 10.Similarly, the top of the central area of the socket is covered by ametal plate 26, (Fig. 4), the outer edge of which is received in arabbet around the upper, inner edge of ring 10. Plates 23 and 26, beingsecured, as by screws threaded into posts 20 or otherwise, to thecentral structure of the socket and being rigidly separated thereby forma guiding track permitting ring 10 to rotate about the center of thedevice. The rotation of ring 10 is limited to the desired amount, bymeans of a slot 27 provided near the outer edge of plate 26 in which apin 2S, carried by ring 10, plays. Bottom plate 23 may be provided witha central conductive stud 30 by means of which contact to the groundterminal of the capacity measuring bridge (not shown) may be made.Plates 26 and 23 are provided with apertures in alignment with contacttubes 22. The apertures in bottom plate 23 extend into the central stud30 as shown at 32 in Figure 4, and are preferably lined with insulatingmaterial, such as glass tubes 33, so that lead-in conductor 14 may notcontact the conductive walls of aperture 32. The apertures in plate 26which are in alignment with contact sleeves 22 are preferably somewhatlarger than the outside diameter of contact sleeves 22, and arecountersunk for the purpose of avoiding accidental contact between plate26 and sleeve 22 and for facilitating the insertion of lead-inconductors 14 into the contact sleeves.

Positive electrical contact between lead-in conductors 14 and thecontact sleeves 22 is provided by spring pressed contact plungers 36which enter contact sleeves 22 laterally through side apertures 38. Froman inspection of Figure 3, it will be seen that the lead-in conductor14, shown in this ligure in section, is tightly pressed against theinterior wall of contact sleeve 22 by the action of plunger 36. Goodelectrical connection is thus assured. However, if the spring action ofplunger 36 is not relaxed when a tube is to be inserted it will be foundthat the long, lead-in wires or terminals 14 tend to buckle when theyencounter the plunger 36 and the insertion of tube 15 into the test setis greatly hampered. Therefore, the rear end of spring wire 40, whichsupplies the spring force to plunger 36, is carried by a sleeve 41 whichhas a closed end 42. Sleeve 41 is in turn slidably received by a secondsleeve 43 having a closed end 44 provided with central aperture 45,through which spring wire 40 passes. A light spring 47 tends to urgesleeves 41 and 43 apart, thus tending to draw plunger 36 out of thecontact sleeve 22. The center conductors of each of the coaxialconnectors 12 each carry a ball end contact 50, which, when it is inalignment with the closed end 42 of sleeve 41, forces the sleeveradially inwardly against the pressure of spring 47, whereby plunger 36is forced into contact sleeve 22 and into engagement with conductor 14.This is the situation shown in Figures l and 4. However, when ring 10 isrotated counterclockwise to a position as Shown in Figure 2, the ballend 50 clears end 42 of sleeve 41, allowing spring 47 to press sleeve 41to the left in Figure 2 as far as it will go. Plunger 36 is therebywithdrawn from contact sleeve 22, whereby lead-in conductor 14 may befreely inserted.

In utilizing the test adapter of the present invention, stud 30 of thedevice is first seated in a socket in the Capacity test set, which isadapted to receive it, ring 10 is then turned counterclockwise until pin28 engages one end of slot 27, when it is known that each of the contactsleeves 22 are open and clear. An electron tube 15 or other device to betested then has its leads straightened and arranged in a circlecorresponding to the diameter of the circle defined by contact sleeves22, the conductors are introduced into the contact sleeves 22 a distancesuch that a minimum length of the lead-in conductors 14 is exposed. Ring10 is then rotated in a clockwise direction until pin 28 engages theother end of slot 27. In this position, each of the ball ends l) of thecentral conductors of the coaxial connectors 12 are in coaxial alignmentwith sleeves 41 and press them radially inward, whereby plungers 36enter apertures 38 in contact sleeves 22 and make good electricalcontact between conductors 14 and the plunger. Thereafter, coaxial cableends. such as the one illustrated at 60 in Figures 1 and 2 are connectedto those of the coaxial cable connectors 12 which are connected to theelements of tube 15 between which it is desired to make capacitymeasurements. All of the remaining coaxial cable connectors 12 are thenpreferably capped by short circuited sections of coaxial transmissionline, whereby the tube electrodes to which they are connected arebrought to ground potential. That is, they are all electricallyconnected to ring 10. By suitably shifting the coaxial lines which areassociated with the capacity testing instrument with relation to theconnectors 12 it is possible to measure the capacity between any pair ofadjacent elements in the tube. lt should be understood that in makingcapacity measurements, a bridge arrangement is employed which issensitive substantially only to the capacity between a pair ofconnections to selected coaxial connectors 12. In general, and withinlimits, the bridge is not sensitive to capacity between each of theseterminals and ground represented by the conductive casing of the socketof the present invention. Therefore, the fact that the capacity betweenthe casing of the socket and the contacts may be rather large does notinfluence the measurement of the capacity between a chosen pair of leads14.

ln order to provide a positive locking position for outer ring lil whenit is in its clockwise position pressing the spring plungers 36 into theconnector sleeves 22, the closed ends 42 of slidable sleeves 41 may beprovided with a concave portion as indicated at 61 in Figure 4. Theconcavity 61 cooperates with the ball end 50 of the inner conductor ofthe coaxial transmission line connectors to act as a detent to hold ringin its operating position.

The main body portion of the test socket may be formed by castingplastic insulating material 16 in a cavity containing the prearrangedshielding members 1S, or by molding the individual sections underpressure, and thereafter drilling out the holes for the spring plungers.Alternatively, individual molded or machined segments of insulatingmaterial 16 may have vthe shielding members 18 painted, sprayed orplated onto the surface. The individual segments thus produced may beinternally drilled and machined to receive the spring pressed plungerarrangement and thereafter the individual sections may be joinedtogether to form a single unitary central body.

While the foregoing description has been predicated on theassumptionthat the socket is particularly adapted to test long, lead subminiaturetubes, it is evident that short, lead tubes may be tested equally Well.By rearranging the number of contact sleeves 22 and their dispositionand size, a test socket may be constructed which may be adapted for anytype of tube. Where tubes having short ilexible leads or conventionalsocket bases are to be tested, the provision of the deep cavity 32 foraccommodating the excess lead length may be unnecessary and may beomitted if desired.

While we have shown and particularly described a number of modicatons ofthe present invention, it should be clearly understood that ourinvention is not limited thereto, but that modifications may be made.

What we claim is:

1. A connector terminal including a contact sleeve adapted to receive aconductive wire, a side aperture in said sleeve, a resilient plungerarranged to enter said aperture laterally of said sleeve, a pair oftelescoping hollow cylinders arranged about said plunger, a springbetween said cylinders urging said plunger away from said Contactsleeve, and cam means for overcoming the effect of said spring wherebysaid plunger is resiliently pressed into said side aperture to bind saidwire in said sleeve.

2. A connector terminal including a contact sleeve adapted to receive aconductor wire, a side aperture in said sleeve, a resilient plungerpassing through said aperture and adapted to grip said wire between saidplunger and the opposite side wall of said sleeve, a spring urging saidplunger out of said aperture, and cam means for disabling said spring tocause said plunger to grip said wire.

3. A test socket including a number of contact sleeves arranged in acircle, radially arranged springs pressing plungers through lateralapertures in said sleeves, further springs arranged to withdraw saidplungers from said sleeves, and cam means for simultaneously disablingsaid further springs whereby said plungers enter said sleeves, saidmeans including a rotatable ring about the interior of said socket andinsulated contact lingers carried by said ring and adapted to be movedinto alignment with said further springs.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,348,394 Douglas Aug. 3, 1920 2,289,172 Beal July 7, 19422,378,294 Field et al. lune 12, 1945 2,537,581 Gaynor Jan. 9, 1951FOREIGN PATENTS Number Country Date 218,995 Switzerland Ian. 15, 1942562,548 Great Britain July 6, 1944 713,417 Germany Nov. 7, 1941 723,428Germany Aug. 5, 1942

